This invention relates to an early warning electrical sound alarm system for pet door structures to signal unauthorized entry or attempted entry through the pet door when the pet door is covered and not in use.
Pet doors adapted for the passage of small animals, such as dogs and cats, into the owners home have gained and continue to gain wide acceptance in the market place. For instance, an extremely successful pet door structure is disclosed in U.S. Pat. No. 2,758,646 issued to Johnson on Aug. 14, 1956. The Johnson pet door structure generally includes a frame defining a passageway therethrough, and a flap swingably mounted on the frame adjacent the upper edge of the passageway for swinging movement in either direction therethrough. Associated with the frame is a pair of interior and exterior solid panels which may be releasably secured on each side of the frame when the pet door is not in use.
To enhance security of the pet owner's home, a need has been expressed for an effective early warning system to signal unauthorized entry through the pet door, for instance by a prowler's hand attempting to reach the inside door knob. Further, it is desirable, if not necessary, to have a self-contained alarm system which may be quickly and easily installed on pet doors of various sizes. The present invention fulfills this need.